<?php
class AliyunOSSAction extends CommonAction {
	public function getSignature(){
		$config = C('ALIYUN_OSS');
		$id= $config['id'];
		$key= $config['key'];
		$host = $config['host'];
	
		$now = time();
		$expire = 30; //设置该policy超时时间是10s. 即这个policy过了这个有效时间，将不能访问
		$end = $now + $expire;
		$expiration = $this->gmt_iso8601($end);
		$dir = $_SERVER['HTTP_HOST'].'/'.$this->siteid.'/';
	
		//最大文件大小.用户可以自己设置
		$condition = array(0=>'content-length-range', 1=>0, 2=>1048576000);
		$conditions[] = $condition; 
	
		//表示用户上传的数据,必须是以$dir开始, 不然上传会失败,这一步不是必须项,只是为了安全起见,防止用户通过policy上传到别人的目录
		$start = array(0=>'starts-with', 1=>'$key', 2=>$dir);
		$conditions[] = $start; 
	
	
		$arr = array('expiration'=>$expiration,'conditions'=>$conditions);
		//echo json_encode($arr);
		//return;
		$policy = json_encode($arr);
		$base64_policy = base64_encode($policy);
		$string_to_sign = $base64_policy;
		$signature = base64_encode(hash_hmac('sha1', $string_to_sign, $key, true));
	
		$response = array();
		$response['accessid'] = $id;
		$response['host'] = $host;
		$response['policy'] = $base64_policy;
		$response['signature'] = $signature;
		$response['expire'] = $end;
		//这个参数是设置用户上传指定的前缀
		$response['dir'] = $dir;
		echo json_encode($response);
	}
	private function gmt_iso8601($time) {
        $dtStr = date("c", $time);
        $mydatetime = new DateTime($dtStr);
        $expiration = $mydatetime->format(DateTime::ISO8601);
        $pos = strpos($expiration, '+');
        $expiration = substr($expiration, 0, $pos);
        return $expiration."Z";
    }
	//显示上传窗口
	function index(){
		$this->display();
	}
}